Several restaurant chains that recently added alcohol to their menus have decided it causes more problems than it’s worth. Customers aren’t buying as many drinks as expected, and selling alcohol is causing many logistical problems.

A restaurant that decides to sell alcohol must obtain permits, train its staff, check ID—which slows down service—and find a stand-alone area for serving alcohol, according to The New York Times.

Starbucks, Sonic and Burger King are among the chains that have tried adding alcohol to their menus. One challenge for fast-food chains is that many of their employees are under the legal drinking age of 21, according to James M. Seff, a lawyer who advises wineries and breweries. “If someone is 18 and a buddy comes in who’s 18, chances are better than otherwise that the minor will serve them,” he told the newspaper. “The regulatory authorities will murder them if there is a pattern in practice of service to minors.”

Sonic, which added beer and wine to the menu in Homestead, Florida, has had to hire security guards to keep underage drinkers away. The company expects its insurance rates will rise.

Starbucks added wine and beer in five stores in the Pacific Northwest to boost its nighttime traffic. A spokesman said feedback has been positive, but the company has not announced any plans to add alcohol to more stores.

Burger King started selling beer at its Whopper Bars, which are designed to be more upscale than its fast-food locations. The company has encountered issues with liquor licenses at some locations, the article notes.